This invention relates to a device-coupled assembly and to a device used therewith and particularly relates to a golf club formed by a shaft which is coupled to a golf club head through a coupling device and further relates to the coupling device.
Golf clubs are typically formed by a shaft which is coupled to a club head. The shaft is formed with a relatively large width or diameter at one end, referred to as the butt end, and a relatively small width or diameter at the opposite end, which is referred to as the tip end. The shaft is typically tapered uniformly from the butt end to the tip end and may be formed with a short cylindrical length at the tip end. The shaft could be formed in other configurations if desired. A hollow stem, commonly referred to as the hosel, is formed with and extends outwardly from the head. The hollowed portion, or opening, of the hosel typically conforms to the shape and size of the exterior of the shaft at the tip end thereof to facilitate assembly of the tip end of the shaft within the hosel. For example, the hosel could be cylindrical for receipt of the short cylindrical length of the tip end of the shaft.
Currently, in one technique for manufacturing golf clubs, the tip end of the shaft is coated with a bonding agent such as an epoxy glue and is then placed into the opening of the hosel. Thereafter the epoxy glue cures to provide a permanent bond between the tip end of the shaft and the hosel to thereby join the shaft to the club head to form the golf club. With such a bonded arrangement between the shaft and the hosel, it is impossible to reverse the assembly without destruction of either, or both, the tip end of the shaft and the hosel of the head. From a practical standpoint, this eliminates the opportunity for the user of such clubs to remove the shaft from assembly with the head.
The ability to uncouple the shaft from the head may be desirable for a variety reasons. For example, the shaft or head of a currently used club may be damaged or worn and the user may wish to keep the component which is not worn or damaged and replace the other component. Also, it may be desirable to transport and or store the shaft independently of the head when the club is not in use in a manner similar to the dismantling of a pool cue stick for the same purpose. Further, there are numerous fitting shops where a golfer can practice and experiment with a number of different golf clubs to determine which club is most suitable for the golfer. In such a practice and experimenting environment, it would be most practical if the golfer could assemble selected shafts with selected heads on an interchangeable basis to locate the optimum combination of shaft and head to further enhance the golfer's playing of the game of golf.
While many coupling devices have been designed over the years for coupling a shaft to a club head, some of these devices are interposed axially between the shaft and the hosel. Thus, such a device forms a portion of the length of the club and presents a potentially weak link in the area of the coupling device. Also, with such a device, there are no laterally overlapping portions of the shaft and hosel which would tend to provide necessary lateral strength when the club is swung to hit a golf ball.
A few coupling devices of past design do allow the tip end of the shaft and the head or hosel to be in lateral alignment. Typically though, devices of this type undesirably add bulk to the club compared to an unaltered club.
Devices of the types noted above, add mass, weight and length to critical areas of a club thereby creating an imbalance in the parameters of the club which could undesirably affect the golfer's swing and impact with the ball.
Thus, there is a need for a device for removably coupling one object, such as a golf club shaft, to another object, such as a golf club head or hosel of the head. There is a further need for such a device where, when comparing the device-coupled club with a directly coupled shaft and head, the presence of the device does not alter the mass of the head and the swing weight and the natural frequency of the club. Further, there is a need for such a device for use in forming a club where, in comparison with the directly coupled club, the mass and the total length of the club remain unchanged by the addition of the device and the length of the tip end of the shaft which is inserted into the head and/or the hosel is the same as the directly coupled club.